Dyskritodon
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Dyskritodon Temporal range: 145–139 Ma |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Subphylum: | Vertebrata |
| Class: | Mammalia |
| Order: | ?†Eutriconodonta |
| Genus: |
†Dyskritodon Sigogneau-Russell, 1995 |
| Type species | |
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Dyskritodon amazighi Sigogneau-Russell, 1995 |
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| Species | |
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Dyskritodon ("tooth of unknown origin", from Greek δυσκρίτος, "dyskritos") is a genus of extinct mammal from the Lower Cretaceous of Morocco, and possibly the Early Jurassic of India. Of uncertain affinities, it is tentatively described as an eutriconodont.
The type species, D. amazighi, is known from the Anoual Syncline deposits in the Atlas Mountains, dating to the Berriasian. It is known from several molars, about 1.85 mm long. These teeth are noted for being rather high and narrow crowned, bearing three main cusps that decrease in height posteriorly, as well as two minuscule mesial cusps.
D. indicus is known from a single lower molar tooth from the Kota Formation, dating to the Hettangian-Pliensbachian. It is very similar to D. amazighi, differing in being smaller (1.24 mm), having a shorter posterior root and some differences in the cusps. However, compared to D. amazighi molars, it is "drastically less complete".
Sigogneau-Russell referred the genus to Eutriconodonta on the basis of its basic triconodont shape. However, she considered it aberrant enough to warrant a separate family within the clade. Further studies have similarly found it rather distinct from other eutriconodonts, and it is listed as an incertae sedis taxon. It is nonetheless more "advanced" than morganucodontids and other basal Mammaliformes.
Due to the large temporal distance between both species, different environments and general incompleteness of the Indian material, there is also doubt as to whereas D. indicus is closely related to D. amazighi. For now, its relationship to it is, too, provisory.
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